1. Field of the Invention
The present invention relates generally to an electronic tuning apparatus used in electronic stringed instruments of a plucked instrument type (e.g., a guitar, bass) and of a bowed instrument type (e.g., a violin), and more particularly, to an electronic tuning apparatus capable of obtaining musical tones having a proper sound frequency which are the same as those obtained by plucking properly tuned strings, depending upon an electronic string tuning method but not upon a mechanical string tuning method.
2. Description of the Related Art
Recently, with a rapid development of electronic technology, various types of electronic stringed instruments have been developed, which employ electronic technique, such as for instance electric guitars, electronic violins, guitar synthesizers and so on. These newly developed stringed instruments have been proposed in place of traditional acoustic stringed instruments, such as Oriental Koto, Indian sitar, violin, guitar and the like.
This electronic stringed instrument is clearly different from the acoustic stringed instrument mentioned above, in its sound-generation mechanism in which a vibration of an extended string is converted into an electric signal and a sound is generated with a desired tone color and sound volume in accordance with said converted electric signal. The electronic stringed instrument, however, has a feature similar to that of the acoustic instrument. That is, in the electric stringed instrument, as in the acoustic instrument, strings are extended with a predetermined tension along the string-depression board (i.e., a fingerboard) and an effective string length for vibration is defined by depressing the string at a predetermined fret position with a finger, wherein a musical tone of a sound frequency defined by the fret position is generated by plucking the depressed string. Accordingly, it is required in the electronic stringed instrument, as in the acoustic stringed instrument, that .circle. all of the individual strings must be extended with a proper tension, respectively, and .circle. each of the strings is extended along the fingerboard with a proper strings length, relative to the fret positions fixedly aligned on said fingerboard. That is, each of the strings must be extended under proper tuning conditions as stated above. A string which is extended with an improper tension and is extended for a distance of an improper string length relative to the fret position may result in a generation of a musical tone of an incorrect sound frequency. In particular, in a guitar synthesizer of a type in which musical tones of various tone colors are generated by a string plucking operation, a string-vibration pitch-information defined by an effective vibration length of a string is extracted, and a generation of a musical tone having a corresponding sound frequency is controlled in accordance with said extracted string-vibration pitch-information, so that, if each of the strings is not extended under proper tuning conditions, an incorrect string-vibration pitch-information is extracted, which results in generating a musical tone of an incorrect sound frequency. Accordingly, each of the strings specially needs to be extended under a proper tuning state.
It is known to those skilled in the art that there are two types of string tuning in which a string is properly tuned. One type of tuning is referred to as a pitch or fine tuning method, in which a tensile strength on an extended string is increased or decreased by a manipulation of bobbin devices (referred to as pegs) mounted on the head of the stringed instrument, thereby the tension on the extended string being controlled. The other type of string tuning is referred to as a harmonic or string length tuning method, in which the length of the string is varied by altering the distance between a pair of the string supports (generally referred to as a bridge, nuts) which support both the ends of the extended string.
In the meantime, a novel tuning apparatus has been developed, which is disclosed in U.S. Pat. No. 4,497,236, and which is capable of accomplishing both the sring tunings in accordance with both the methods stated above almost at the same time. The tuning apparatus has been developed to overcome disadvantages that when the tension on the string and the string length are to be corrected in accordance with the conventional method, the string tension control mechanism and the string length control mechanism must be independently manipulated to set the proper tuning state, which requires troublesome and time consuming tuning work. By the tuning apparatus, the tension on each of the strings can be increased or decreased, while each of the strings is firmly restrained at its one end after the length of the string is properly set, that is, without changing the string lengths which have been properly set, so that the tuning apparatus permits obtaining the proper tuning state relatively easily and rapidly compared with the conventional tuning apparatus.
Even in the event of setting the proper tuning state by the use of the tuning apparatus mentioned above, there are still disadvantages that the mechanical tuning work is required, such as fine adjustment work for tension control member and the string supported member, and moving these members in the direction of the neck of the stringed instrument.
Even in the case, each of the strings is tuned in proper conditions before performance, frequent operations during the performance can often result in a disturbed tuning condition for the strings, such as arming operations by a tremolo arm (operation to modulate musical tones by evenly raising and/or lowering their sound frequency), bending operations with a finger (operation to raise and/or lower the sound frequency of the generated musical tone by transversely moving the depressed string after picking the string), sliding operation (operation t modulate the sound frequency of the generated musical tone after picking the string by sliding the finger depressing the string longitudinally along the string). If this unfavorable problem is occurring , it is hard to immediately readjust the instrument to a proper tuning condition during the short interval up to the following performance, and consequently, there is still another disadvantage that the player cannot help continuing to play the instrument with unintentional sound frequencies.
Furthermore, it is difficult for a beginner to adjust to the proper tuning condition for each of the strings and the beginner often extends the string with an excess tension, resulting in breaking the string. There is still one more disadvantage that in order to prevent from occurring the situation mentioned above, professional work must be asked for a string tuning operation and/or help of other tuning instrument is especially needed.